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03-19-2017, 05:13 PM #1
Tungaloy twisted TDX indexable drills vs the Sandvik 880's
Our company recently began manufacturing more of our parts. We needed to drill 3,4, and 5xd holes in 17-4 Stainless steel with an indexable drill, and we talked to Tungaloy representatives in our area, including one individual who staffed the Tungaloy booth at last years IMTS show in Chicago.
The reps recommended Tungaloy Twisted drills. They showed me a drill- the drill really looked impressive- nice nickel plated finish, nice geometry etc. We bought 7 or so of the twisted drills at their recommendation.
It took us ~4 months to begin making chips on the machines these were intended for. We hired a 20+year mill-turn machinist to lead the new turning cell. Our machines have 25HP main spindles and 1000PSI M30-70 chip blasters, running Master Chemical Trim E206 coolant at 10% concentration [we've been thinking about going to Qualachem Xtreme Cut 292 but haven't yet]. We had a lot of trouble getting the Tungaloy drills to perform consistently. After about 4 days working with the drills, having damaged one TDX340W40–4 4Xd holder body and replaced it with a TDX340W40–5 5xd body, we had them at about 290SFM, pushing a feed of about .0041”/Rev. We had tried speeds up to 450SFM, and feeds .0035-.0059/rev. The smoothest we could get the drills to be, they screamed like an apparition, and made the machines vibrate in the 3-5Xd depth region. At their worst, they made the concrete vibrate and the machines seemed about ready to start walking around on the floor. We really felt like we were beating up our brand new machines using the TDX drills. Some insert edges would go 20 minutes, others 7 or 13, and the process was so unstable the machinist couldn’t really leave 1 machine to check a part at another. After drilling a few hundred holes, we realized part of the insert used in the initial cut would later be used and part of another edge. So there really were only 2 ACTUALLY CLEAN insert edges per insert set. (This doubles the cost of a pair of inserts). The marketing suggested 4 edges, but our practical application showed 2 real indexes per insert set. That probably was the condition causing spotty insert life. The production rate was slow under ideal conditions with the Tungaloy drill, and slower with the machinist second guessing and checking the insert condition, having to stop machines when inserts chipped or failed prematurely etc.
We switched products to the Sandvik 880-D3400L40-05, and instantly the unstable process stabilized. We tuned the drill in only 2-3 cuts (25 minutes of production time) and settled on 391SFM at .0055/rev. The drilling time per hole decreased by 45% [51 seconds faster per hole]. The 880 gave us Fanuc tracked tool life of 13 minutes per insert edge, and gave us 4 predictable indexes. The machine vibration was gone. Spindle loads dropped substantially. Feed loads dropped 30%. We drilled over a thousand holes on one body, and our machinists were able to operate 3 machines and get their focus and efficiency back.
Production speed greatly increased, and we drilled over a thousand holes on the Sandvik 880-D3400L40-05 without an issue. Our second Sandvik drill to go into a machine- a A880-D0625LX19-03, was tuned in 2 cuts, and produced 1500 holes.
The Tungaloy product for us was a waste of time and money. The first drill body was destroyed in a couple dozen holes. The tuning time cost us $1000 of payroll, and probably several times that in lost production time. Sandvik mops the floor with the competition. It’s not really even comparable. The only negative point for Sandvik is the higher insert cost. The drill body costs are comparable, but the insert pricing makes them a little less attractive. We’ve had trouble getting decent discount pricing on sandvik inserts and tools so we do as little business with Sandvik as possible unfortunately. Iscar is where we currently do probably 60% of our purchasing.
03-20-2017, 12:44 AM #2
drills with 2 inserts are less stable than drills with 1 insert
this is why you find holders for :
... 2 inserts : 3D, 4D ,5D stop
... 1 insert : 3D, 5D, 7/8D, 10D, etc
those damaged holders may be repaired, so to use them again
about machine load, a quick reaction time should protect it
an insert with 4 cutting edges may not allow using all 4 edges, but only 2 : depends on wear, etc
outer insert tends to bend the holder, so is better to have it in good condition, while the inner insert may continue cutting
holders for 2 inserts last less long, because the insert is clamped with a small screw, and the thread may fail
also, they may start having problems at 4,5D, thus friction inside the hole
overall, inserts are less expensive when compared to tools with 1 insert, and this reduces costs with tools
i use kyocera drx ; etc etc etc ; kindly !
03-20-2017, 07:46 AM #3
I'm not sure what the exact purpose of the original post was, but I agree with the message 100% - higher performance tools are more expensive, and they are more than worth the added cost...
I work for a competitor to Sandvik, but I have nothing bad to say about them. I'm glad that you guys found a worthy solution to the problem. I cringe when see many of these less-expensive tooling companies giving away free cutter bodies, yet people continue to fall for it... (If something seems too good to be true, it usually is...)
Thanks for sharing at least.
03-20-2017, 09:06 AM #4
03-20-2017, 09:06 AM #5
That's a long rant with little substance. 880 to TDX is entirely apples to oranges, of course results will be different.
I'm a big fan of the 880 drills and have a lot of them, but in Tungaloy's defence their equivalent for heavy duty drilling is the TungSixDrill and it is also very good. I expect you would have had equally better results if you had moved to it instead of the 880.
Shop Supply Guru liked this post
03-20-2017, 10:01 AM #6
03-20-2017, 10:22 AM #7
03-20-2017, 11:06 AM #8
TungdrillTwisted - Tungaloy Corporation
First, the cutting-speed at the center is zero, and at the periphary, is WFO... So there's an exceptional difference in speed & thrust forces being placed on the insert at the periphary vs. the center.
This means that compromises in the chip-breaker geometry & carbide grade must be made to allow for the differing speeds, and thrust-loads between the cutting conditions at the periphery & center.
In the drill pictured above, the inserts are also positioned so that there's a lot of the insert that's unsupported in the Z-axis thrust direction. At the periphery, the the insert won't have as much support for interruptions etc, which might not be a huge deal, although it may be needed on entrance & break-out.
That drill body also has a lot of helix, and I'm not sure what kind of material it's made from... Could be soft-steel, case-hardned & plated, thru-hardened...?
----- ----- ----- ----- -----
I'm going to brag on our indexable drills (Seco Perfomax) for a moment, to show the contrast between cheaper tools, and more expensive tools... (The Sandvik 880 drill would fall into much of what I'm going to describe too, btw...)
The 1st, most obvious difference, is that more expensive, higher-performing indexable drills will have different inserts at the periphery & center. This does away with most of the compromises of the above design, because it allows you to tailor the grade/geometry better for the specific cutting conditions each insert will face. On our Seco Perfomax drills, the outer insert gets a much harder grade, and often a very heat-resistant coating, due to the higher cutting speeds at the periphery of the drill. The center inserts however, gets a tougher grade, specific chip-breaker geometry, and a thin TiN coating for maximum toughness against the high-thrust forces, but also for lubricity & chip-forming at the slower cutting speeds. (Zero at the exact center...)
In the case of Seco drills and Sandvik 880's alike, they both use square inserts, although still different between the center & periphery inserts. This shape makes the insert stronger, tougher, and allows the pocket to offer more support for the insert as well. As a result, these drills have no problems with interruptions, or rough/cast surfaces on entrance, and/or break-out.
They also have slower/less helix on the flutes, which is supposed to make the drill body more rigid as well. And in the case of the Seco drill, (I can't speak for others hear, but I'm sure we're not alone) the drills are made from thru-hardened pre-heat treated material. Which means that we control the hardness/toughness of the material, and then machine to final dimensions. This helps with the toughness & vibration tendencies of the drill as well...
Regardless how similar many of these indexable drills look at first glance, they are not created equal...
Seco Performax drill - DP3 inserts - YouTube
Perfomax full demo - YouTube
(If you don't want to watch the entire length of the video, at least skip to the end...)
ManualEd liked this post
03-20-2017, 12:00 PM #9
03-20-2017, 11:39 PM #10
one more thing : such inserts may get wear without a visible breaked edge
their edge may look intact, only a little darker
this may fool the operator, making him believe that the tool may still perform well
you can predict that, by monitoring spindle effort, or by changing inserts regulary, even if they still look ok
and the output hole is not always equal with the tool diameter ( attached imaged )
such deviations exist, but this fact is not shared by all tool dealers
for example, o26 has tolerances [ -0.1 .. +0.2 ]
... this does not mean that the output hole tolerance is [ -0.1 .. +0.2 ]
... output hole tolerance will be as for a drill with a single insert
... but the nominal will be inside the [ -0.1 .. +0.2 ]
... consider 2 tools, on 2 machines :
...... one may deliver o26.2 h7
...... the others one may deliver o25.9 h7
...... tolerances is keeped as long as inserts are "new"
this behaviour of the tool has no conection with the fact that it may be used excentric kindly !
03-21-2017, 04:19 AM #11
03-21-2017, 04:36 AM #12The big strength of the 880 is that after an edge has failed it will continue drilling and make it out of the hole in one piece, long after any other drill would be welded to the workpiece
however, at this moment, you may damage the screws that are holding the insert
depends what cutting specs are used
if cutting specs are high and an insert breaks, than load monitoring may save your holder
if cutting specs normal and an insert breaks and there is no load monitor, maybe it will continue cutting
you can push this tools by using load monitor
03-26-2017, 03:32 PM #13
The Tungaloy reps came back in and talked to me. They started with a statement about not wanting me to be stuck with the drills and wanting to work with me. I took that to mean a return, and in the spirit of compromise I offered to take 60 cents on the dollar of what I paid for the inserts and drills I had.
They backpeddled into trying to sell me other Tungaloy products. I was busy and I wasted about an hour talking with them and they left without doing anything for me. They are an IMC group company and we have a lot of Iscar products but the Tungaloy catalog is really short on real solutions compared to Iscar. I'm not really sure any of the IMC companies stand behind product. I had some Iscar Sumo cham drill inserts that shit the bed (flat inserts don't like 17-4) and the rep heard about it, and didn't offer anything. Those guys should really work on not sticking the customer with garbage. It isn't cool. If my shit doesn't work, I eat that. My customer doesn't eat my failures.
That was Thursday. Yesterday I bought about 6 Sandvik 880 drills and a couple thousand dollars worth of inserts. I also looked for a sandvik shirt on Ebay- figuring I'd like to have a Sandvik T-shirt. The drills are really performing- solving problems and I'm happy with Sandvik. There were no shirts - apparently Sandvik doesn't sell logo apparel.
I put 2 880's (a 1.187" 4xD and a 25mm X's D) into the cut yesterday (Saturday) working a settup with my lead guy- another 17-4 job, and the drill tuning process took 1 hole for each drill. We increased SFM 10% from 390 to 430. The 1.187 was running .004/rev, and the 25mm .0036"/rev (subspindle jaws grab weaker than our royal quickgrips on the main, and we don't want to push the part with the 25mm on the sub).
Nice low noise, low vibration cutting- I know those two tools are going to be part of a stable process that will get parts out of the machines. We have 2300 parts to make on that settup and that's BIG. Process stability has to be high.
03-26-2017, 11:28 PM #14
about cutting specs :
... We increased SFM 10% from 390 to 430 > this change is too little, and does not matter the operator may overide feed or rapid with more than 10% .... yes, it matters, is positive, is more, but is not so more if you ask me
... 1.187 was running .004/rev, and the 25mm .0036"/rev > [o30mmx0.1mm/o] + [o25mm*40/36*0.1] > this is10% faster than 0.1
main factor for drills is feed, not rpm
i will give you an example about the o25 :
... your current cutting spec : 1600*0.1=160 mm/min
... also 1300*0.123=160 mm/min
... if machine stable at above specs, than restore initial rpm : 1600*0.12=190 mm/min
i don't know how long is that drill, etc, but i can tell that your feeds are low or at least the tool may ask for more feed, but maybe the cnc can not take it
there are tools cheaper than ISCAR that perform almost the same
do you have load monitor on the machine ? and if yes, what is the reaction time ? kindly !
03-27-2017, 03:32 AM #15
The 880 is still the best drill on the market even after the 15 years or so it has been available, so you will not be disappointed with your investment. Especially so if the bulk of your work is tougher materials. On soft steels for example the 880 is not so great, but it can be made to work all the same.
I wasn't suggesting that you should have stuck with Tungaloy necessarily, I was only pointing out that you were not using their most suitable tool. The TDX is what I consider to be a very light duty drill but it too has it's place, it has a light cutting action and good chip forming ability and works very well for deep holes in certain materials.
Sandvik will work with you on a good discount if you buy a reasonable quantity from them, and buy direct.
03-27-2017, 06:10 AM #16
one more thing : this file, shared a few post ago, http://global.kyocera.com/prdct/tool..._cp252_1_e.pdf, contains usefull information about such tools
so far i have not seen them at other vendors : i mean i only saw a part, but nothing that was not also in that file
if you have time, pls check pages :
... 7, low half
... 17 - 19
bending behaviour, cutting tolerances, stability, alignments, etc all there